Imaging in anterior glenohumeral instability

Area of Science:

• Orthopedics
• Radiology
• Sports Medicine

Background:

• Shoulder range of motion is balanced against vulnerability to injury and instability.
• Glenohumeral instability presents with a wide spectrum of clinical findings.
• Diagnosis can be challenging, with imaging findings varying from obvious bone defects to subtle labral or capsular lesions.

Purpose of the Study:

• To review imaging findings in three distinct clinical scenarios of shoulder instability: acute first-time dislocation, chronic recurrent dislocation, and chronic instability without recurrence.
• To discuss the biomechanics of dislocation and pathophysiology of associated injuries.
• To differentiate imaging findings in acute versus chronic instability and guide the role of various imaging modalities.

Main Methods:

• Review of imaging findings in acute first-time shoulder dislocation.
• Review of imaging findings in chronic instability with repeated dislocation.
• Review of imaging findings in chronic instability without repeated dislocation.
• Discussion of biomechanics, pathophysiology, and imaging modalities including MRI arthrography and specialized views.

Main Results:

• Imaging findings differ significantly between acute traumatic dislocations and chronic unstable shoulders.
• Subtle labral abnormalities and capsular lesions can be associated with instability.
• Specific imaging modalities and views are crucial for accurate diagnosis depending on the clinical scenario.

Conclusions:

• Imaging plays a critical role in diagnosing and characterizing shoulder instability.
• Tailoring imaging protocols and interpretation to the specific clinical presentation is essential.
• Accurate imaging identification of lesions aids in treatment planning for glenohumeral instability.